The present invention relates to a lock cylinder. More particularly, the present invention relates to a lock cylinder that includes a housing and a plug.
Generally, lock cylinders include a housing and a plug that define respective pin chambers to receive pin pairs. The pin pairs include outer pins substantially disposed within the housing, and inner pins disposed within the plug. Springs are often used to bias the pin pairs toward a key slot in the plug. More specifically, the springs are engaged with the outer pins, which in turn engage the inner pins and force the inner pins into the key slot. In the absence of a correct or appropriate key, the outer pins are partially disposed in the plug and block rotation of the plug within the housing.
The plug is rotatable relative to the housing in most conventional lock cylinders. A shear line is defined where the plug and the housing come together. When an appropriate key is inserted into the key slot, the inner and outer pins are moved. The junctions of the inner pins and the outer pins are aligned with the shear line, which allows the plug to be turned to a locked or unlocked position. In other words, the appropriate key will move the inner and outer pins such that the outer pins are disposed completely in the housing, and the inner pins are disposed completely in the plug.